Departamento de Ciências Agrárias, Instituto de Biotecnologia e Bioengenharia - Centro de Biotecnologia dos Açores, Universidade dos Açores Angra do Heroísmo, Portugal.
Instituto de Biologia Molecular e Celular, Universidade do Porto Porto, Portugal.
Front Plant Sci. 2014 Mar 20;5:102. doi: 10.3389/fpls.2014.00102. eCollection 2014.
Endosperm transfer cells in maize have extensive cell wall ingrowths that play a key role in kernel development. Although the incorporation of lignin would support this process, its presence in these structures has not been reported in previous studies. We used potassium permanganate staining combined with transmission electron microscopy - energy dispersive X-ray spectrometry as well as acriflavine staining combined with confocal laser scanning microscopy to determine whether the most basal endosperm transfer cells (MBETCs) contain lignified cell walls, using starchy endosperm cells for comparison. We investigated the lignin content of ultrathin sections of MBETCs treated with hydrogen peroxide. The lignin content of transfer and starchy cell walls was also determined by the acetyl bromide method. Finally, the relationship between cell wall lignification and MBETC growth/flange ingrowth orientation was evaluated. MBETC walls and ingrowths contained lignin throughout the period of cell growth we monitored. The same was true of the starchy cells, but those underwent an even more extensive growth period than the transfer cells. Both the reticulate and flange ingrowths were also lignified early in development. The significance of the lignification of maize endosperm cell walls is discussed in terms of its impact on cell growth and flange ingrowth orientation.
玉米胚乳转移细胞具有广泛的细胞壁内突，在核发育中起关键作用。尽管木质素的掺入会支持这个过程，但在之前的研究中并没有报道过这些结构中存在木质素。我们使用高锰酸钾染色结合透射电子显微镜-能量色散 X 射线光谱以及吖啶橙染色结合共聚焦激光扫描显微镜，使用淀粉胚乳细胞作为对照，来确定最基部的胚乳转移细胞（MBETC）是否含有木质化的细胞壁。我们研究了用过氧化氢处理的 MBETC 超薄切片的木质素含量。通过乙酰溴法还测定了转移细胞和淀粉细胞细胞壁的木质素含量。最后，评估了细胞壁木质化与 MBETC 生长/突缘内突方向的关系。在我们监测的细胞生长期间，MBETC 细胞壁和内突都含有木质素。淀粉细胞也是如此，但它们的生长时间比转移细胞长得多。在早期发育过程中，网状和突缘内突也都木质化了。本文讨论了玉米胚乳细胞壁木质化对细胞生长和突缘内突方向的影响。
